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Portions not contributed by visitors are Copyright 2018 Tangient LLC
TES: The largest network of teachers in the world
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Questions, hypotheses and variables are all connected in science. These are the key parts of any scientific investigation. Understanding how these three ideas work together will make your project go smoother and help you to get a reliable answer to your question.
Below are three examples that should help you to see how these ideas work together. But first let’s define the important types of variables.
Manipulated or Independent Variable
Manipulated or Independent Variables are things that the research changes in some way to look for an effect. When you compare two different things, the things are the manipulated or Independent variable. Manipulated means altered or changed, while Independent means one its own. These two terms can be used interchangeably.
Responding or Dependent Variable
The Responding or Dependent Variable is usually the one a researcher uses to compare things. If you are interested in the difference between two plants you might measure height, weight, leaf number, root mass, color, leaf shape, leaf area, age... All of those measurements would be Responding or Dependent Variables. As above the two terms can be used interchangeably.
Control
A control is a variable that the researcher keeps the same across all of their experimental trials. By keeping the controls the same, the researcher ensures that the controls are not responsible for any of the results.
Scientific Questions and Hypotheses
A scientific question asks about relationships between variables.
Example:
Question: Does more bacteria grow on wooden or plastic cutting boards?
Hypothesis: Wooden cutting boards will have more bacteria.
Variables:
Identify each variable as Manipulated or Responding; Independent or Dependent; or a something to Control.
Graph of Hypothesis:
Example # 2
Question: Does the amount of air in a ball affect how high it will bounce?
Hypothesis: Balls with more air will bounce higher than balls with less air.
Variables:
Identify each variable as Manipulated or Responding; Independent or Dependent; or a something to Control.
Graph of Hypothesis:
Example: One manipulated variable and change over time
Question: Do radish plants grow more quickly with added nitrogen?
Hypothesis: Plants with added nitrogen will grow more quickly.
Variables:
Identify each variable as Manipulated or Responding; Independent or Dependent; or a something to Control.
Graph of Hypothesis:
Example : More complicated with two dependent variables
Question: How is snowmaking snow different from natural snow?
Hypothesis: Snowmaking snow will be more dense and have less shape.
Variables:
Identify each variable as Manipulated or Responding; Independent or Dependent; or a something to Control.